Aim: To explore the prognostic value of certain complete blood count parameters and ratios in COVID-19 patients with the definitive diagnosis.

Methods: We compared certain parameters of the complete blood count test, which are related to inflammation, between the inpatient/outpatient and the survivor/non-survivor groups to determine whether they have a prognostic role. Analyzes were performed in Statistical Package for the Social Sciences (SPSS). Parametric data were expressed as arithmetic mean±standard deviation, and nonparametric data were expressed as median (Q1-Q3). The relationship in categorical variables was examined with Chi-Square. Receiver Operative Characteristics (ROC) analysis determined cut-off values for mortality. P <0.05 was considered statistically significant.

Results: A total of 6343 patients ≥18 years old were included in the study; 4822 (76.0%) were outpatients, and 1521 (24.0%) were inpatients. 53.5% (3.396) of the patients were female, and 46.5% (2947) were male. The mean level of mean platelet volume (MPV), white blood cell count (WBC), plateletcrit (PCT), neutrophil count (NEU), red cell distribution width (RDW), platelet distribution width (PDW), neutrophil/lymphocyte ratio (NLR), monocyte/lymphocyte ratio (MLR) and platelet/lymphocyte ratio (PLR) were higher in the inpatients compared to the outpatients (p<0.05 for all). Also, the mean hemoglobin (HGB) and lymphocyte (LYM) were significantly lower in the inpatients (p<0.05 for both). On the other hand, compared to the survivors, the non-survivors had significantly higher WBC, NEU, RDW, NLR, MLR, MPV, and PLR, and lower HGB, LYM, PCT, and PLT levels (p<0.05 for all).

Conclusion: RDW, HGB, WBC, MPV, PLT, LYM, NEU, NLR, MLR, and PLR have been shown to have a robust relationship with poor prognosis of COVID-19.

Keywords: Complete blood count parameters, COVID-19, inflammation, prognosis